In UMTS (Universal Mobile Telecommunications System) networks, for the purpose of improving spectral efficiency, peak data rates, etc., by adopting HSDPA (High Speed Downlink Packet Access) and HSUPA (High Speed Uplink Packet Access), it is performed exploiting maximum features of the system based on W-CDMA (Wideband Code Division Multiple Access). For the UMTS network, for the purpose of further increasing spectral efficiency and peak data rates, reducing delay and the like, Long Term Evolution (LTE) has been studied (for example, see Non-patent Document 1). In LTE, as distinct from W-CDMA, as a multiple access scheme, the scheme based on OFDMA (Orthogonal Frequency Division Multiple Access) is used in downlink, and the scheme based on SC-FDMA (Single Carrier Frequency Division Multiple Access) is used in uplink.
As shown in FIG. 1, signals transmitted in uplink are mapped to appropriate radio resources, and are transmitted from a mobile terminal apparatus to a radio base station apparatus. In this case, user data (UE (User Equipment) #1, UE #2) is assigned to the uplink shared channel (PUSCH: Physical Uplink Shared CHannel). Meanwhile, control information is time-multiplexed with the PUSCH when the control information is transmitted concurrently with the user data, and when only the control information is transmitted, is assigned to the uplink control channel (PUCCH: Physical Uplink Control CHannel). The control information transmitted in uplink includes downlink quality information (CQI: Channel Quality Indicator), retransmission response signal (ACK/NACK) to the signal of the downlink shared data channel (PDSCH: Physical Downlink Shared CHannel), etc.
In the PUCCH, typically, different subframe configurations are adopted between the case of transmitting the CQI and the case of transmitting ACK/NACK (see FIGS. 2A and 2B). In the subframe configuration of the PUCCH, one slot (½ subframe) contains 7 SC-FDMA symbols. Further, one SC-FDMA symbol contains 12 information symbols (subcarriers). More specifically, as shown in FIG. 2A, in the subframe configuration (CQI format (PUCCH formats 2, 2a, 2b)) of the CQI, a reference signal (RS) is multiplexed into a second symbol (#2) and sixth symbol (#6), and the control information (CQI) is multiplexed into the other symbols (first symbol (#1), third symbol (#3) to fifth symbol (#5), seventh symbol (#7)) in a slot. Meanwhile, as shown in FIG. 2B, in the subframe configuration (ACK/NACK format (PUCCH formats 1, 1a, 1b)) of ACK/NACK, a reference signal is multiplexed into third symbol (#3) to fifth symbol (#5), and the control information (ACK/NACK) is multiplexed into the other symbols (first symbol (#1), second symbol (#2), sixth symbol (#6), seventh symbol (#7)) in a slot. In one subframe, the slot is repeated twice. Further, as shown in FIG. 1, the PUCCH is multiplexed into radio resources at opposite ends of the system band, and frequency hopping (Inter-slot FH) is applied between two slots having different frequency bands in one subframe.